Characteristics of Neoplasms and Epidemiology MCQs

Lymphatic spread is more typical of carcinomas , whereas haematogenous spread is favoured by sarcomas . Reference: Robbins and Cotran Pathologic Basis of Diseases, 10 th ed, Pg: 196.

Differentiation refers to the extent to which neoplasms resemble their parenchymal cells of origin, both morphologically and functionally; lack of differentiation is called anaplasia. In general, benign neoplasms are composed of well-differentiated cells that closely resemble their normal counterparts. Reference: Robbins Basic Pathology, 10 th ed, Pg: 192.

Metastasis is defined as the spread of a tumour to sites that are physically discontinuous with the primary tumour, an event that unequivocally marks a tumour as malignant. The spread of cancer cells from the place where they first formed to another part of the body. In metastasis, cancer cells break away from the original(primary) tumor, travel through the blood or lymph system, and form a new tumor in other organs or tissues of the body. Metastasis is a pathogenic agent's spread from an initial or primary site to a different or secondary site within the host's body; the term is typically used when referring to metastasis by a cancerous tumor. The newly pathological sites, then are metastases. Reference: Robbins and Cotran Pathologic Basis of Diseases, 10 th ed, Pg: 272-273.

The staging of solid cancers is based on the size of the primary lesion, its extent of spread to regional lymph nodes and the presence or absence of blood borne metastases. Reference: Robbins and Cotran Pathologic Basis of Diseases, 10 th ed, Pg: 236.

Invasion, and metastasis, the major causes of cancerrelated morbidity and mortality, result from complex interactions involving cancer cells, stromal cells and the extracellular matrix(ECM). These interactions can be broken down into a series of steps consisting of local invasion, intravasation into blood and lymph vessels, transit through the vasculature, extravasation from the vessels, formation of micrometastases and growth of micrometastases into macroscopic tumors. Predictably, this sequence of steps may be interrupted at any stage by either host-related or tumor-related factors. For the purpose of discussion, the metastatic cascade can be subdivided into two phases: (1) invasion of ECM and (2) vascular dissemination and homing of tumor cells. Reference: Robbins Basic Pathology, 10 th ed, Pg: 220.

Ans. is None "Because benign and malignant pheochromocytomas may have an identical histological appearance, the only absolute criterion of malignancy is metastasis." "The diagnosis of malignant pheochromocytoma is made only when metastasis is demonstrated."